From DE 10 2004 038 464 A1 a generic piston is known, in particular a cooling duct piston, of an internal combustion engine with an upper part and a lower part, which are able to be produced separately from one another and are subsequently able to be joined together, wherein the upper part has at least three radially encircling joining webs and the lower part likewise has at least three radially encircling joining webs, which are brought together during the joining process and via which the upper part is securely connected with the lower part.
From DE 100 28 926 A1 a composite piston is known, having a piston crown of highly heat-resisting material and a lower part containing the hubs, wherein the piston crown and the lower part are connected with one another by a central screw connection. In order to prevent the entry of combustion gases into the piston, the piston crown sits in its outer region with a conical or convex support surface on the lower part or on an intermediate part, wherein between the upper part and the lower part a separating plate is arranged, which separates a cooling duct, present in the lower part, from a cavity present in the upper part.
Highly stressed Otto and diesel engines nowadays already require intensive efforts in order to be able to also guarantee the durability of aluminium pistons in the long term. Through the ever rising temperatures, due to the increase in output, an increasingly rising heat input occurs in the region of piston rings and piston lands, which leads to an increased build-up of oil carbon on the piston rings and in particular in the groove base. This oil carbon layer, in turn, functions as an insulator and can contribute to the overheating of the piston rings and therefore to a damage thereto.